1. Field of the Invention
The present invention relates to host bus adapters, and more particularly to testing host bus adapters with PCI-Express port logic.
2. Background of the Invention
Storage area networks (“SANs”) are commonly used where plural memory storage devices are made available to various host computing systems. Data in a SAN is typically moved between plural host systems (that include computer systems, servers etc.) and storage systems (or storage devices, used interchangeably throughout this specification) through various controllers/adapters.
Host systems typically include several functional components. These components may include a central processing unit (CPU), main memory, input/output (“I/O”) devices, and streaming storage devices (for example, tape drives). In conventional systems, the main memory is coupled to the CPU via a system bus or a local memory bus. The main memory is used to provide the CPU access to data and/or program information that is stored in main memory at execution time. Typically, the main memory is composed of random access memory (RAM) circuits. A computer system with the CPU and main memory is often referred to as a host system.
Host systems often communicate with storage systems via a host bus adapter (“HBA”, may also be referred to as a “controller” and/or “adapter”) using an interface, for example, the “PCI” bus interface. PCI stands for Peripheral Component Interconnect, a local bus standard that was developed by Intel Corporation®. The PCI standard is incorporated herein by reference in its entirety.
PCI-Express is another Input/Output (“I/O”) bus standard (incorporated herein by reference in its entirety) used in this environment. PCI-Express uses discrete logical layers to process inbound and outbound information.
Various other standard interfaces are also used to move data between host systems and storage devices. Fibre channel is one such standard. Fibre channel (incorporated herein by reference in its entirety) is an American National Standard Institute (ANSI) set of standards, which provides a serial transmission protocol for storage and network protocols such as HIPPI, SCSI, IP, ATM and others.
HBAs that are placed in SANs receive serial data, align the serial data and then convert it into parallel data. A HBA determines data boundary before performing the alignment operation. A comma character is often used by the HBA to determine character and word alignment in a serial stream of data. Once a comma character is detected the HBA assumes that the received character/words are on the same boundary. Hence, it is important for a HBA to properly detect comma (or any other special character) characters in a bit stream in order to correctly process data thereafter. A HBA typically uses a state machine (or other piece of hardware) to detect comma characters and perform the alignment.
Conventional systems do not provide an efficient methodology to periodically test a HBA's ability to detect comma characters and then perform the re-alignment. Therefore, there is a need for a method and system that can generate random data and test a HBA's ability to detect comma characters and reacquire correct alignment, if needed.